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Topic: Computer SPDIF vs Standalone CD Player (Read 5794 times) previous topic - next topic
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Computer SPDIF vs Standalone CD Player

Greetings.

The question is this. If a cd is ripped to a harddrive with EAC and the PCM stream fed to an external DAC via TOS link, is this pcm stream then comparable to that from an expensive CD player's PCM stream?

This would assume that there is a decent sound card,non-resampling etc. The quality of the DAC would make a difference but I am just wondering about the quality of the basic PCM stream.

A friend of mine has a very nice Sony CD player and we have been back and forth a bit on this question.

Especially on a lightly or moderately scratched cd,I believe the initial step of reading with EAC will yield the more accurate version of the song, but even with brand new "virgin" cd's, I notice that EAC is busy a few times correcting the odd sector via re-reads of bad sectors.

Is the error correction of a standalone capable of that type of accuracy?

Computer SPDIF vs Standalone CD Player

Reply #1 –
if you're after more accurate streams, then it depends more on the hardware (and EAC of course)

a good CD burner with accurate stream, c2, etc would be good.

if i had infinite resources i'd have myself a plextor drive and be ripping with plextools, which apparently gives better results than EAC.

as far as audible difference goes... i'd never ever notice, but that's no reason to not get good equipment (if you have the disposable income to think this way, then good luck to you )

Computer SPDIF vs Standalone CD Player

Reply #2 –
Thanks for the response.

My question was to ask if the drive and optics of an expensive cd drive can deliver as accurate a stream to an external DAC, as a hardrive with an EAC ripped wav being fed to the external DAC via SPDIF through a decent soundcard?

I agree that this would be inaudible to the average listener either way, and that the situation is hypothetical in that sense.

My knowledge of standalone error correction is not great, but when I used to sell the stuff 10 years back, the techs would talk about interpolation from other channels and such.

They were ways to make errors inaudible. But they were still just patched errors.
And there were no players that would go back and check anything twice.

If your connection to the DAC is secure, is coming off your harddrive theoretically better than a standalone if your soundcard is up to snuff?

Computer SPDIF vs Standalone CD Player

Reply #3 –
There is no EAC quality issues with "virgin" cd's and good drives. The PCM should be identical. Damaged discs with C2 errors are a different issue as stanalone cd players are better in masking these errors (making artifacs less audiable). Also I never noticed any EAC error correction taking place on "virgin" cd's - even on some scratched ones. Deep scratches yes, otherwise no.

Sound cards, DAC have nothing to do with this. Basicaly if your CD's rip without C2 errors then you should never hear a difference, but badly damaged discs should do better on standalone.

Computer SPDIF vs Standalone CD Player

Reply #4 –
Quote
Sound cards, DAC have nothing to do with this. Basicaly if your CD's rip without C2 errors then you should never hear a difference, but badly damaged discs should do better on standalone.

The soundcard would have an effect if it was resampling,especially if it is doing a poor job like many older sound blaster cards.

As far as virgin cd's go, check and see if all tracks rip with 100% quality. If not, then some re-reading and comparison was required. What is the standalone doing with the small errors that EAC can so easily correct?

If we use your example of a badly scratched cd, I agree the standalone would mask the errors better,but it is still just patching the data stream. The error is still there.

With a computer, you can just resurface the disc to get an error free rip.

Computer SPDIF vs Standalone CD Player

Reply #5 –
Quote
As far as virgin cd's go, check and see if all tracks rip with 100% quality. If not, then some re-reading and comparison was required.

IIRC less than 100% quality doesn't necessarily matter - it just means EAC had to work a little to recover the data but if it didn't report errors occured then the rip was perfect.
Was that a 1 or a 0?

Computer SPDIF vs Standalone CD Player

Reply #6 –
Quote
IIRC less than 100% quality doesn't necessarily matter - it just means EAC had to work a little to recover the data but if it didn't report errors occured then the rip was perfect.

This is exactly my point.

What does the standalone do with the small errors that EAC corrects by re-reading?

If the errors are not corrected but only patched by interpolation etc, then technically the stream from the harddrive would be more accurate.

Computer SPDIF vs Standalone CD Player

Reply #7 –
Yes, the standalone players are accurate. If they were not, they would break red book standards (one error per hour).
I've checked my Yamaha CDX860 with pressed and burned CDs, for 5 minutes of playback. Zero errors.
I've just checked an old Micromega Microdrive audiophile drive (nearly dead, both the optical block and main engine get sometimes stuck). Pressed CD track 1, and burned CD last track. Zero errors.
Oliver Friedman, in the EAC mailing list told me that he did the same with a Sony player, for a complete CD. There were only several isolated errors (one, two or three, something like that).

You can't compare the quality of EAC reading with a CD Player quality. The first difference is speed. CD Players are optimized for, and read at 1x speed, while EAC rips at max speed, where the drive's accuracy is on the edge (if it could rip faster without errors, it would, and would be sold more expensive).
The second difference is that EAC performs burst mode ripping (or synchronized burst mode, called fast, or secure burst mode, or paranoid burst mode, but still burst mode), while a CD Player performs a sequential reading, which eliminates the risk of synch errors, that are not always detected by EAC (my Teac 540e suffers from this problem, so I can't use it for ripping. Even secure mode test and copy doesn't detect the skips, because they are consistent).

Another problem is the poor grounding of computer power supplies, that can let external interferences in, which can in turn cause losses of stream in the SPDIF coaxial output. I tried hard to get rid of them, but I had to use optical instead.

But audiophiles' main concern is not errors, but jitter. They pretend that jitter in the SPDIF stream can have an audible effect. This has never been completely dismissed by technical studies. The most complete I saw, from an article of the AES calculated that in the worst case, that is a 0 db 20 kHz sine played at 110 db, the best CD Player in the world (with <10 ps of jitter) would still produce distortion above the threshold of audition.
However, with SPDIF streams, another concern is the jitter rejection of the DAC, discussed here : http://www.hydrogenaudio.org/forums/index....showtopic=11909 , because the total jitter is the sum of what remains of the incoming jitter, and the DAC clock jitter.

I never heard about a blind test showing an audible difference between different SPDIF sources, or cables. I planned one with a guy in an audiophile shop, for the end of the month. He already lent me his CD drive (the MicroMega I spoke of above), telling me that if I could not hear the difference with my Yamaha, he would pay me a visit to the otolaryngologist... I hope that he know one not too expensive, because I didn't hear any. Now, it is his turn to prove me that he can hear a difference.
Because of material reasons, the test won't be double blind, but I'll try to have it as close to double blind as possible. It should not cause problems. With a friend, we already miserably failed some single blind tests.

Computer SPDIF vs Standalone CD Player

Reply #8 –
Thanks Pio.

But how would you rate a secure EAC rip wav being played through a good sound card via a well cabled spdif out?

Surely this a mathematically acceptable way in terms of errors per min as well?

Would even an error per min be eliminated?

Didn't you test the spdif outs of a whole bunch of cards and find they were bit perfect as well?

Computer SPDIF vs Standalone CD Player

Reply #9 –
I would rate it perfect, as any SPDIF out of any CD Player.

I just tested my own card (Marian Marc 2) in loopback for a short time. There were no errors.

Computer SPDIF vs Standalone CD Player

Reply #10 –
Quote
I would rate it perfect, as any SPDIF out of any CD Player.

Good (relief) 

What of the scratches though? Does Red Book specs allow for that?

If they are reading at 1x speed over a scratch, how can they check the accuracy of the data?

Computer SPDIF vs Standalone CD Player

Reply #11 –
Of course, the specs are valid for unscratched CD only 

They check the accuracy of the data exactly as CD ROM do, with C1/C2 error correction. The difference being that their ability to conceal uncorrectable errors is a bit better than current CD ROM drives, because more attention is given to the audio quality, and that the reading is more stable, because they don't rush into the speed race with competiting models, and the reading is sequencial, thus no synch error is possible, only read errors.

Computer SPDIF vs Standalone CD Player

Reply #12 –
OK.

But if its reading at 1x speed and hits a significant scratch, the standalone will patch as best it can but cannot reconstruct the error. And I havn't seen a player yet that reports if the errors are occuring.

By transferring to harddrive as described, is this problem not largely eliminated?

I am not trying to resurrect the debates about EAC's accuracy etc.

It just seems to me that having a wav file that has been double checked for error then re-read until the error is corrected (if possible), is the way to fly, rather than accepting the patched version offered by the standalone.
 

Computer SPDIF vs Standalone CD Player

Reply #13 –
Quote
But if its reading at 1x speed and hits a significant scratch, the standalone will patch as best it can but cannot reconstruct the error.


The same is true for a CD ROM drive. I don't see any difference. The errors that EAC can correct are most of the times local inconsistencies due to too fast a reading speed, too poor a CDR media, or a dying drive. With scratched CDs, EAC has been reported many times to perform quite bad.

Quote
And I havn't seen a player yet that reports if the errors are occuring.


That's right.